For recent dialysis apparatuses serving as blood purification apparatuses, there are some technical proposals in which not only dialysis treatment (HDF or HF) but also priming, blood returning, and substitution (emergency fluid infusion) are performed with dialysate that is to be supplied to a dialyzer. In such a dialysis apparatus, the dialysate in a dialysate introduction line is supplied to a blood circuit (an arterial blood circuit or a venous blood circuit) by activating a substitution pump.
In the above dialysis apparatus, work of connecting one end of the substitution line to a collecting port provided at a predetermined position of the dialysate introduction line is necessary. Therefore, whether or not the connecting work has been done normally needs to be checked. Hence, there are some related-art proposals for dialysis apparatuses each performing a testing process in which a flow route provided with a collecting port is pressurized by activating the substitution pump or a duplex pump, and the resulting increase in the pressure or a retainment of that pressure is detected and evaluated, whereby the connection of the substitution line to the collecting port is checked (see PTL 1 and 2, for example), the teachings of which are expressly incorporated by reference herein for all purposes.
PTL 1: Japanese Unexamined Patent Application Publication No. 2011-161060
PTL 1: Japanese Unexamined Patent Application Publication No. 2012-192101
However, since the above known blood purification apparatuses each employ a displacement-type pump, such as a substitution pump or a duplex pump, for the pressurization in the testing process, the following problems arise.
A displacement-type pump is characterized in that the value of pressure increase after a specific number of revolutions or the reciprocating movements varies with the position of the rotor or the plunger and in that it takes time for the pressure to reach a predetermined value. In particular, in a peristaltic pump such as the substitution pump, the value of pressure increase or the time of pressure increase vary depending on the adjustment of the gap between the rotor and the stator. Therefore, the connection of the substitution line to the collecting port cannot be checked instantly and accurately. There is another problem in that since the substitution pump or the duplex pump is used during blood purification treatment, the testing process cannot be performed during the treatment.